In the first half of the nineteenth century it was generally believed that reactions of organic compounds proceeded with minimal structural change. This tenet simplified the elucidation of the numerous substitution, addition and elimination reactions that characterized the behavior of common functional groups.
In the 1970s the solderless breadboard (AKA plugboard, a terminal array board) became available and nowadays the term breadboard is commonly used to refer to these.Breadboard is also a synonym for  prototype .Because the solderless breadboard does not require soldering, it is reusable. This makes it easy to use for creating temporary prototypes and experimenting with circuit design.n the 1970s the solderless breadboard (AKA plugboard, a terminal array board) became available and nowadays the term breadboard is commonly used to refer to these.
Yeast in bread making. Yeast is used for the leavening of bread. Yeast uses the sugars and oxygen in dough to produce more yeast cells and carbon dioxide gas. This is called multiplication. The carbon dioxide makes the dough rise which gives the bread a light and spongy texture. Yeast also works on the gluten network.